[FIX] mail: disable multiline channel

This avoid text flickering when a multiline channel name is hovered in the
discuss sidebar.

task-2274991

closes odoo/odoo#63100

X-original-commit: 6a3d8982a657fc4e124f6bebe457289297efdabe
Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>

addons/mail/static/src/components/discuss_sidebar_item/discuss_sidebar_item.scss

@@ -15,6 +15,7 @@
 .o_DiscussSidebarItem_activeIndicator {
     width: $o-mail-discuss-sidebar-active-indicator-width;
     align-self: stretch;
+    flex: 0 0 auto;
 }
 
 .o_DiscussSidebarItem_command {
@@ -51,6 +52,7 @@
 .o_DiscussSidebarItem_name {
     overflow: hidden;
     text-overflow: ellipsis;
+    white-space: nowrap;
 
     &.o-editable {
         margin-left: $o-mail-discuss-sidebar-active-indicator-width + $o-mail-discuss-sidebar-active-indicator-margin-right;

addons/mail/static/src/components/thread_icon/thread_icon.scss

@@ -1,4 +1,3 @@
-
 // ------------------------------------------------------------------
 // Layout
 // ------------------------------------------------------------------
@@ -7,6 +6,7 @@
     display: flex;
     width: 13px;
     justify-content: center;
+    flex: 0 0 auto;
 }
 
 .o_ThreadIcon_typing {